If both methods have the same signature, as it is the case in your example, only one implementation is possible. In this case, there is no way to implement two versions of the method for the two interfaces. So yes, the example will suffice.
If the signature is the same for the two methods, but they have different return types, this will result in a compilation error.
If the two methods have different signatures, there can and have to be two different implementations.
